1. Field of the Invention
The present invention relates to an IP telephone system, and a calling method by the IP telephone system that perform communication via an IP network.
2. Description of Related Art
The recent rapid growth of the Internet has drawn attention to an IP telephone system that enables low-cost voice communications with telephone apparatuses at remote places as well as free voice communications between IP telephone apparatuses owned by subscribers. It is also known that, when a PSTN (Public Switched Telephone Network) telephone apparatus connected to a conventional PSTN places a call to an IP telephone apparatus, a telephone number which begins with “050” is dialed.
Recently, ENUM technology has drawn attention due to its ability to effectively manage information used for various communications methods including telephones, facsimiles, cellular phones and electronic mail, and to enable various communication according to individual circumstances. ENUM is designed to identify the Internet service with a unique global identification number such as the E.164 number, using the DNS (Domain Name System). Currently, the IETF (Internet Engineering Task force) is seeking to standardize ENUM platforms, where protocol specifications are discussed (See Publication 1, for example).                [Publication 1] Issued by ENUM Trial Japan “ENUM Trial Japan First Report” May, 2004        
When dialing a telephone number beginning with “050” using the ENUM system, however, a user needs to input a telephone number at an IP telephone. However, the user is unable to input a telephone number using a telephone number search system that enables the user to search a telephone number via a PC.